John alves



(N0 Model.)

4J. ALVES. Furnace fQr Steam'Boilers.

' Patented March 3,. 1881.

WITNSEES:

Unire@ gramas Paritair Ormea.

JOHN ALVES, OF DUNEDIN, NEW ZEALAND.

FURNACE FOR STEAM-BOILERS.

SPECIFICATION forming part of Letters Patent No. 238,546, dated March 8, 1881.

Application led November 8, 1880.

To all whom it may concern.'

Be it known that I, JOI-IN ALVES, of Dunedin, New Zealand, have invented certain new and useful Improvements in Furnaces for Steam-Boilers and other purposes, of which the following is a specification.

My invention relates to the furnaces of locomotive or other steam boilers; and it consists in the peculiar construction and arrangement of the parts, as hereinafter more fully set forth.

Figure l of the drawings annexed gives a longitudinal section of the lire-box of a locomotive-boiler provided with myimprovements. Fig. 2 is a sectional plan thereof, and Fig. 3 is a cross-section in front ofthe fire-bridge and tube-sheet.

As illustrated, f f indicates the grate or fire bars, which are supported in the usual manner on the cross bearing-bars 7c 7c, and preferably incline, as is commonly the case, toward the tube-sheet t of the boiler-being, say, two inches lower at this end than at the front end.

At the back of the rebox is arranged a lire-bridge, h Z) s, of peculiar construction. This bridge is supported on the back ends of the grate-bars, and rests aga-instthe tube-sheet. The lower part, b, is preferably formed of castiron; but it may also be formed of nre-brick, and is perforated with a number of air-slots, s, while the upper part, lt, which is imperforate, is preferably made of lire-brick, in two sections of L shape, the horns of which rise on each side of the tube-sheet, as shown best in Fig. 3. The slots s of the lower part are made preferably in the manner shown, commencing with a vertical slot at the center, followed by a parallel series of oblique slots on either side thereof, inclining in opposite directions, with wide horizontal slots over the same, as illustrated. The slotted part of the bridgecasting is set out from the tube-sheet, leaving an air-chamber, R, between the two, which communicates with the air-chamber or ash-pit below the grate, while a lian ge, a, projects from the top of the casting over the air-space and closes against the tube-sheet, and the tirebrick sections h h rest upon this tlanged top, bein g secured thereto by bolts passing through molded holes in the brick and screwing into tapped holes in the casting, as seen best in Figs. l and 3. Fire-clay is packed between (No model.)

dered sufficiently air-tight and the heads 0f 6o the said bolts protected from the intensity of the llame.

The grate-bars are set out from both the ends and sides of the fire-box, as shown, so that a good volume of air can freely rise up between the same and along the sides of the lire-box, to render the iiame more energetic on the sides of the tire-box, and in the upper part thereof, securing a more even distribution of the heat over the walls of the lire-box. I have found in practice that locomotives fitted with my improvement show from twenty to forty more pounds of steam on inclines than when fitted with the ordinary grates; and I iind that with any kind of coal, and in any grate, even in common stoves, a much greater heating effect is obtained by the use of the beveled-edged grate-bars than is the case with common bars.

1f desired, the hollow and slotted part of the lire-bridge may be continued all around the sides of the fire-box, but for most furnaces this will not be necessary. The feature which I consider particularly novel in this bridge is the hollow slotted lower part, arranged and operating as described, the form and arrangement of the slots therein, and also the form and arrangement of the upper part of the bridge, which rests against the tube-sheet and rises on either side thereof, around the out-line ofthe series of tubes therein.

To rake the gra-te I provide a poker or rake liavin g serrated teeth on its raking-face to lit on and between the beveled edges of the gratebars, and thus effectually rake the grate, when required.

It will be observed that the lugs on the sides of the grate-bars, which serve to keep them separated at the proper distance, lie below the beveled edges of the bar, so as not to interfere with the action of the serrated rake, as will b e readily understood.

IOO

ing of the lower part, b, provided with a vertical and inclined and horizontal slots s, and Bange a, surniounting the air-chamber R, and imperforate upper part., h, and bolted to the lower part, Z1, the whole being supported on the ends of the grate-bars, substantially as described, and for the purpose set forth.

JOHN ALVES.

Vhat I claim as my invention is- 1. The combination, with the grate-barsff, set ont from the tubesheet to leave on airpassage between them, ot' the lire-bridge sup- 5 ported by the grate-bars and consisting of the lower part, b, provided with e vertical and inl clined and horizontal slots, s, and flange ce, surmounting the airchamber R, (ind the imperforate upper part, 7L, secured to the lower part,

1o b, substantially as described, and for the purpose set forth.

2. The rire-bridge herein described, consist- VVitnesses THOMAS GALLMAN, CHAS. W. ELY. 

